There is an increasing demand for functionality and reduced size and weight for portable wireless products, such as handsets, personal digital assistants (PDAs), and personal computer (PC) notebooks. In addition to market demands for small, thin, low-cost and lightweight wireless communication devices, the convergence of wireless telephones and computers is further driving the need for functional circuits designed with the smallest and lowest cost printed circuit board (PCB) manufacturing technology. As a result, the PCBs in these devices increasingly require higher routing densities. High Density Interconnect (HDI) technologies, also known as build up technologies, have been developed to accommodate high density routing. For an HDI PCB, vias can be formed using an non-reinforced dielectric such as a Resin Coated Foil (RCF) or prepreg and using processing techniques such as laser drilling and photo imaging. The vias are typically metalized using electroless copper/electrolytic plating. One advantage of the HDI construction includes the ability to create smaller vias and via pad sizes. This enables higher routing density, lower metal count, reduced board area and increased functionality as compared to traditional PCBs. HDI further improves the wiring density by using build up microvias in the outer layers. Unfortunately, however, the staggered via hole structure results in dead space on certain layers where components cannot be mounted and lines cannot be wire connected. Nevertheless, HDI technologies provide a cost effective and timely means for manufacturing PCBs for wireless devices.
Interstitial via hole manufacturing technologies allow the use of buried and blind vias and do not require mechanically drilled vias since any two layers are electrically connected by a IVH (Interstitial Via Hole). Since the IVH can be placed in any position, no through hole disturbs interconnections between features on other layers. As a result, dead space on the PCB is reduced. The increasing reduction in cost to manufacturing an IVH PCB has further made these technologies attractive for manufacturing PCBs for wireless devices. An example a IVH manufacturing technology is the Any Layer Interstitial Via Hole (ALIVH®). ALIVH® is a registered trademark of Matsushita Electric Industrial Co., Ltd.
Conventional PCB design techniques, however, are limited in that a PCB layout designed for one manufacturing technology must be significantly modified in order to manufacture the PCB in another manufacturing technology. As a result, cost and time savings in using an alternate manufacturing technology is not readily available with conventional PCB layout designs and methods.
Therefore, there is a need for printed circuit boards (PCB) and PCB design systems allowing for manufacturing using multiple PCB manufacturing technologies.